Carbonizing cloth



Jul 3, 1945. w. RIDLEY 2,379,653

CARBONIZING CLOTH Filed April 24, 1943 Patented July 3, 1945 caaaomzmc cno'rn Walter miner, Chelmsford, Mesa, assignor to Bill! a Lombard, Inc., Lowell, Man, a corporation of Massachusetts 4 Continuation of application Serial No. 416,598, October 25, 1941. This application April 24, 1943, Serial No. 484,428

4 Claims.

This invention relates to an improvement in a method and apparatus for treating cloth, and more particularly to carbonizing the cloth, the present application being a continuation of my copending application for patent, Serial No. 1:16,- 598, filed October 25, 1941. The purpose of carbonizing is to remove objectionable cellulosic matter such as cotton fibers, burrs, straw, wood splinters, etc., from cloth made of wool or other animal fibers. The cloth is usually first treated with a suitable acid, e. g. sulphuric acid or the like, then dried in any well known manner, and then passed through a carbonizing or baking chamber wherein the cloth is so treated that the objectionable matter is consumed or carbonized, any carbon residue left in the cloth being so friable that it can easily be eliminated by beating or crushing after the cloth has left the carbonizing chamber.

Heretofore the cloth in the carbonizing or baking chamber has been subjected to streams of heated air blown over the surface of the cloth at it passes through the chamber, or to heat radiated from steam coils among or over which the cloth travels. However, such procedure results in an uneven application of heat, and the uneven temperatures so created cause cloudiness, spots or streaks or other variations from uniformity in appearance of the cloth. Moreover, the effective carbonizing temperature has not heretofore exceeded 250 F.'to 300 F. whereas by this invention an efiective carbonizing temperature of from 550 F. to 600 F. is attained.

High temperatures, 1. e., those substantially above 250", in drying or carbonizing woolen cloth have always been found dangerous and troublesome since they cause the natural wool oils or other impurities to vaporize from the cloth. These vapors are carried by the air streams or surrounding air medium until exhausted from the baker or until the temperature has lowered so that they condense from the air. This condensate forms a sticky acid mass which, upon cooling, is very difiicult to remove, and if it gets on the cloth, forms a permanent resist. However, in accordance with prior practice, temperatures much over 300 were diflicult to attain since they depended upon the temperature of the steam supplied in the mill as the source of heat.

The present invention makes it possible to obtain a high effective carbonizing temperature without diiiiculty and at the same time to avoid the objectionable results heretofore attendant upon the use of a high temperature since the cloth passes so very rapidly through the baker,

in a period of the order of fifteen seconds rather than the nine to ten minute period according to the prior practice. Thus the animal fibers of the cloth rarely reach a temperature of 300 before the cloth leaves the baker and hence no substantial vaporizing of oil or other impurities can take place.

The primary object of the present invention is to provide an improved method of carbonizing cloth comprising the treatment of the cloth by the direct impact of infrared heat rays whereby the objectionable celluiosic matter is rapidly destroyed without impairing the animal fibers of the cloth.

a A further object of this invention resides in the provision of an improved carbonizing apparatus or baker comprising a pair of parallel, spaced apart sources of infrared radiant heat, and means by which one or more runs of the cloth are so guided between said sources that the rays of heat emanating from one source impact directly upon one surface of the cloth and the rays of heat emanating from the other source impact directly upon the other surface of the cloth. Specifically one embodiment of this invention comprises a housing defining a carbonizing or baking chamber, a pair of parallel, spaced apart banks of infrared bulbs, and rollers by which the cloth is guided in three parallel vertical passes between said banks.

Other objects of this invention include the provision of means for varying the amount of infrared energy emanating from the sources, and the provision of means by which the distance between the sources may be altered.

These and other objects of the invention will be apparent from a consideration of the following description of one embodiment of the invention and a consideration of the accompanying draw.- ing in which such embodiment is illustrated and in which Fig. 1 is a view in elevation of a carbonizing baker embodying this invention, one side wall of the housin being removed; and

Fig. 2 is a cross-sectional view on the line 2--2 of Fig. 1.

The carbonizing baker l0 shown in the drawing comprises a housing I! which defines a carbonizing chamber M in which the cloth is treated. The side walls iii of the housing ii are rigidly mounted upon a frame comprising crossbeams I8 and posts 20. Channel beams 22 at the top and bottom of the housing are rigidly secured to the crossbeams l8. The housing includes a top plate 24 mounted upon the upper crossbeams l8 and bottom plates 20 mounted upon the lower crossbeams ll. Each end wall II includes a rectangular frame 30 provided at its top and bottom corners with roller mountings 32 which ride in the channels of beams 22 as shown in Fig. 2. Relative movement of the end walls 20 is preferably, but not necesarily, simultaneous and may be attained by any suitable means. As shown in the drawing, a pair of shafts ll, mounted in bearings 38 carried by the posts 20, is employed. Each shaft is provided with right-hand and lefthand screw threads, respectively, which mesh with internally threaded blocks 30 secured to the side posts of the frame 30. A cross shaft 40, rotatable by a handle 42, acts through bevel gears 44 and II to rotate the shafts 3| simultaneously and thereby to move the end walls 28 toward or from each other.

The end walls 28 carry sources-f radiant energy, specifically banks of infrared bulbs, each bank including a board 50 fixed to the inner face of the frame 30 and a plurality of heat radiant bulbs 52 mounted thereon. The bulbs 52 are standard infrared bulbs for example General Electric or Westinghouse R-40 250 watt d ying lamps having tungsten filaments and a color temperature of 2500 K. and provided with reflectors. Current is supplied to the bulbs in any suitable manner, not shown, but since, in the illustrated installation, current supply from a 550 volt line is contemplated, the bulbs, being designed for use on a 110 volt line, are assembled in series in groups of five. As indicated in Fig. 2, the groups are so arrangedthat when all the bulbs are not in use, a complete substantially uniform pattern covering the entire board can nevertheless be attained.

The cloth 00 to be treated is guided in a plurality of vertical 1 asses through the baking chamber midway between the banks of bulbs. From a truck or a dryer (not shown) the cloth passes over a friction roller 82, under an idler roller 6!, and over a guiding roller 80 int the chamber ll through a slot in the top Plate 24. Rollers B8 and I0, and II and 14, mounted at the bottom of the chamber, and rollers 18 and 18 at the top of the chamber guide the cloth in three vertical parallel passes. After the third pass is completed, the cloth is guided below an end wall 20 over a roller 80 to a roller 82 of the folder (not shown) to which the cloth is delivered. Suitable means is provided for advancing the cloth but forms no essential part of the present invention and is not shown in the drawing. The cloth passes up to the roller 18 and then down again into the baking chamber ll through slots in the plate 24. The rollers and I4 which are supported below the lower crossbeams are enclosed by a removable cover plate 84 carried by the bottom plates 26.

Casters 80 at the bottom of the housing I! facilitate the movement of the dryer to any desired location. Windows 00 in the side walls It permit visual inspection of the cloth under treatment. Such windows are removable when desired to afford access to the drying chamber ll.

The vertical passes of cloth are here shown as three in number, but the number may be increased or decreased if desired. However, in order that both faces of the cloth be subjected to direct impact or the infrared rays emanating from the sources of radiant heat, there should be that as it travels through the various passes it is continuously subjected to heat action and the ob- Jectionable celluloslc matter throughout the entire thickness of the cloth is quickly attacked and destroyed. It has been observed that if a thermocouple, having a bulb with a clean bright wire, be inserted in the baking chamber, it does not indicate a temperature substantially above 300 F., whereas if the bulb be blackened with lamp black or if it be placed in contact with a black surface Within the baking chamber, the thermocouple will indicate a temperature of from 550 to 600 F. In the practice of th present invention the cloth is usually carbonized before it is dyed, and hence, when subjected to the carbonizing treatment, it is light in color and highly reflective. However, it is acidulated before it is treated, which results in slightly darkening the cellulosic impurities. These darker impurities, like the blackened bulb of the thermocouple, selectively absorb the infrared rays, and as they progressively blacken in response to the infrared treatment, they are very quickly raised to a temperature of approximately 550 to 600 F., resulting in an extremely rapid and thorough carbonization -of these impurities, whereas the lighter colored animal fibers of the cloth pass through the baking chamber without ever reaching a temperature of more than approximately 300 F. Thus, the animal fibers are not weakened or otherwise inlured by the heat treatment, nor are the volatiles driven oil. Even though there be little initial difference in the color of the animal fiLer and cellulosic impurities the latter are denser and selectively absorb heat more rapidly than the animal fibers and quickly rise to carbonizing temperature. v

In bakers made according to this invention, the rays of heat from the infrared bulbs penetrate the cloth and, if any dampness be present, the drying of the cloth progresses outwardly from the center so that no acid is trapp d and hence no resist or acid burns appear. Moreover, in this baker the air in the baking chamber is not positively set in motion by blowers or the like as in former types.

It will be understood that, although one embodiment of this invention has been shown and described in detail, the invention is not limited thereto and that the illustrated embodiment may be modified or other embodiments made without departing from the spirit and scope of the invention as set forth in the accompanying claims.

I claim:

1. Apparatus for use in carbonizing cloth made from animal fibers but containing vegetable impurities and which has been previously acidulated and is substantially dry, said apparatus comprising walls defining a closed chamber in which the air is substantially quiescent, two opposite walls of the chamber being relatively movable toward and from one another, each of said movable walls supporting a bank of heat-radiating infrared bulbs, the bulbs forming each bank being so distributed and so connected to a source of electrical current as to constitute a substantially uniformly distributed source of energy whether all or only a portion of the bulbs constituting each bank are energized, means for guiding the web of cloth in a run which is substantially parallel to said opposite movable walls and which is between the banks of bulbs, a plurality of screw-threaded elements connecting said oppositely movable .walls, and a single actuating device for turning all of said threaded elements thereby to move the walls relatively toward and from each other while maintaining their parallel relation thereby to vary the intensity of energy received by the run of cloth.

2. Apparatus for use in carbonizing cloth made from fibers of animal origin but containing vegetable impurities and which has been previously acidulated and is substantially dry, said apparatus comprising a rigid frame carrying plates which constitute the walls of a closed chamber in which the air is substantially quiescent, said frame having upper and lower pairs of parallel channel members, two opposite vertical walls of the chamber being relatively movable and having rollers which are guided by said channel members, the frame having bearings for a plurality 01' parallel, rotata'ble actuating rods, each rod having screw-threaded portions of opposite pitch, each of the screw-threaded portions of each rod having threaded engagement with a member carried by one of the respective movable walls, means f or turning all of said rods simultaneously thereby to cause the movable walls to approach or recede from each other, a bank of infrared bulbs mounted on the inner side of each of said movable walls, and means for guiding a web of the cloth in a vertical run in a plane substantially parallel to said movable walls and between said banks of bulbs.

.3. Method of carbonizing cloth made from wool or other animal fibers but containing vegetable impurities and wherein the previously acidulated and substantially dry cloth is subjected to a carbonizing treatment for a period of from 10 to 15 seconds only, characterized in that the vegetable impurities are raised to a carbonizing temperature of the order of 550 to 600 F. by subjecting them to inirared heat rays while concomitantly maintaining the body of the cloth at a temperature below that which would volatilize its natural oils.

4. Method of carbonizing cloth made from wool or other animal fibers but containing vegetable impurities and wherein the cloth, previously acidulated, is traversed through a chamber wherein it passes a source of infrared heat rays, said source being so constructed and arranged that the heat rays impinge upon the cloth and are distributed substantially uniformly widthwise of the cloth, characterized in that the cloth passes the heat source at a velocity such that whereas the light colored body portion of the cloth never attains a temperature exceeding approximately 300 F., the darker colored vegetable impurities become heated to a carbonizing temperature of the order of 550 F. to 600 F.

WALTER RIDLEY. 

